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Cillium exposes sensitive information included in the cilium-bugtool debug archive

High severity GitHub Reviewed Published Apr 22, 2026 in cilium/cilium • Updated Apr 25, 2026

Package

gomod github.com/cilium/cilium (Go)

Affected versions

< 1.17.15
>= 1.18.0, < 1.18.9
>= 1.19.0, < 1.19.3

Patched versions

1.17.15
1.18.9
1.19.3

Description

Impact

The output of cilium-bugtool can contain sensitive data when the tool is run against Cilium deployments with WireGuard encryption enabled.

Users of WireGuard Transparent Encryption are affected.
The sensitive data is the WireGuard private key (cilium_wg0.key) used for node-to-node encrypted communication

cilium-bugtool is a debugging tool that is typically invoked manually and does not run during the normal operation of a Cilium cluster. It is also invoked when gathering sysdumps using the Cilium CLI's cilium sysdump command.

Patches

This issue affects:

  • Cilium v1.19 between v1.19.0 and v1.19.2 inclusive
  • Cilium v1.18 between v1.18.0 and v1.18.8 inclusive
  • All versions of Cilium prior to v1.17.15

This issue has been patched in:

  • Cilium v1.19.3
  • Cilium v1.18.9
  • Cilium v1.17.15

Workarounds

There is no workaround to this issue.

Users who have previously shared bugtool or sysdump archives from WireGuard-enabled nodes should rotate the WireGuard keys on the affected nodes. This can be done by deleting the key file and restarting the Cilium agent, which will generate a new key pair.

Acknowledgements

The Cilium community has worked together with members of Isovalent to prepare these mitigations. Cillium extends special thanks to @kodareef5 for reporting the issue and @tklauser for their work on triaging and remediating this issue.

For more information

If there are any questions or comments about this advisory, please reach out on Slack.

Cilium strongly encourages the reporting of suspected vulnerabilities to the security mailing list at security@cilium.io. This is a private mailing list for the Cilium security team, and the report will be treated as top priority.

References

@peoyekunle peoyekunle published to cilium/cilium Apr 22, 2026
Published to the GitHub Advisory Database Apr 25, 2026
Reviewed Apr 25, 2026
Last updated Apr 25, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

EPSS score

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

Cleartext Storage of Sensitive Information

The product stores sensitive information in cleartext within a resource that might be accessible to another control sphere. Learn more on MITRE.

CVE ID

CVE-2026-41520

GHSA ID

GHSA-gj49-89wh-h4gj

Source code

Credits

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